The role of metallographic microscope in the process control of PCB board technology
The role of metallographic microscope in PCB board slicing technology in process control
The production of PCB board is a process in which various processes cooperate with each other. The quality of the product in the previous process directly affects the production of the next process, and even directly affects the quality of the final product. Therefore, the quality control of the key process plays a vital role in the quality of the final product. As one of the detection methods, metallographic section technology is playing an increasingly important role in this field.
The role of metallographic microscope in the process control of PCB board slicing technology has the following aspects
The role in the inspection of incoming raw materials
As the copper-clad laminate required for the production of multi-layer PCB boards, its quality will directly affect the production of multi-layer PCB boards. The following important information can be obtained from the slices taken by the metallographic microscope:
Copper foil thickness, check whether the copper foil thickness meets the production requirements of multilayer printed boards.
The thickness of the insulating dielectric layer and the arrangement of the prepreg.
In the insulating medium, the warp and weft arrangement of glass fibers and the resin content.
Defect information of laminates The defects of laminates mainly include the following types:
(1) pinhole
Refers to a small hole that completely penetrates a layer of metal. For multilayer printed boards with higher wiring density, such defects are often not allowed.
(2) pits and pits
Pockmarks refer to small holes that do not completely penetrate the metal foil: pits refer to local dot-like protrusions of the pressed steel plate that may be used during the pressing process, resulting in a mild sinking phenomenon on the pressed copper foil surface. It can be determined whether the existence of the defect is allowed by measuring the size of the small hole and the depth of the sag through the metallographic section.
3) Scratches
Scratches refer to thin and shallow grooves drawn on the surface of copper foil by sharp objects. The width and depth of scratches are measured by metallographic microscope sections to determine whether the existence of the defect is allowed.
(4) Wrinkles
Wrinkles are creases or wrinkles in the copper foil on the surface of the platen. The existence of this defect visible through metallographic section is not allowed.
(5) Lamination voids, white spots and blisters
Lamination voids refer to the areas where there should be resin and adhesive inside the laminate, but the filling is not complete and there are missing areas; white spots occur inside the substrate, and the phenomenon of separation of glass fiber and resin at the fabric interweaving is manifested in Scattered white spots or "cross patterns" appear under the surface of the substrate; blistering refers to the phenomenon of local expansion and local separation between the layers of the substrate or between the substrate and the conductive copper foil. The existence of such defects depends on the specific circumstances to decide whether to allow it.
